Quick Answer
Speed work includes any running session done at a harder effort than your normal easy pace — tempo runs, intervals, threshold efforts, fartlek, hill repeats, and strides. One to two quality sessions per week, with the rest of your running at easy pace, is enough to produce significant improvements in speed and race performance.Why Speed Work Matters
Easy running builds your aerobic base — the engine that powers everything you do as a runner. Speed work makes that engine more powerful and more efficient. Without it, your body adapts to one pace and stays there.
Speed sessions target two key physiological systems. Your VO2 max is the maximum amount of oxygen your body can use during hard exercise — the higher it is, the faster you can run before hitting your limit. Your lactate threshold is the pace at which lactate accumulates faster than your body can clear it, causing that burning, heavy-legged feeling. Speed work raises both of these ceilings, which means every pace below them feels easier.
The practical result is simple: races that once felt hard start feeling manageable, and paces that once seemed impossible become your new normal.
Types of Speed Work Explained
Tempo Runs
A tempo run is a sustained effort at your lactate threshold — the pace that feels “comfortably hard.” You can speak in short phrases but not hold a conversation. For most runners, tempo pace is roughly 25 to 30 seconds per kilometre slower than their 5K race pace.
Tempo runs teach your body to clear lactate more efficiently, which directly translates to holding a faster pace for longer in races. A typical session is 20 to 40 minutes at tempo pace, sandwiched between a warm-up and cool-down. Start with 15 minutes and build gradually over weeks.
Tempo runs are the backbone of half marathon and marathon training, but they benefit runners at every distance. For detailed session structures, read our tempo run training guide. If you are new to the concept, our guide on what a tempo run is explains the basics.
Threshold Runs
Threshold runs are closely related to tempo runs but sit at a slightly higher intensity — right at or just below your lactate threshold. The distinction is subtle: tempo runs are sustained and steady, while threshold work can include intervals with short recovery (for example, three sets of 10 minutes at threshold pace with two minutes easy between).
Threshold training is particularly effective for 10K to half marathon runners who need to sustain hard efforts for 40 to 90 minutes. Our guide on threshold runs covers how to find your threshold pace and structure sessions.
Interval Training
Intervals are repeated efforts at a pace faster than your race pace, separated by recovery jogs or rest periods. They target your VO2 max and running economy — making you faster by raising your aerobic ceiling.
Interval sessions vary by distance and purpose. Short intervals of 200 to 400 metres at mile pace build raw speed and neuromuscular coordination. Longer intervals of 800 metres to 1.6 kilometres at 5K to 10K pace build speed endurance and VO2 max. The recovery period between efforts is critical — it must be long enough to allow you to maintain quality on the next repetition.
A simple starting session: six repetitions of 400 metres at 5K pace with 90 seconds recovery jog. As fitness builds, progress to longer intervals or shorter recoveries. Our interval training workouts guide provides sessions for every level, and our guide on interval running for beginners covers how to introduce this type of training safely.
Fartlek
Fartlek — Swedish for “speed play” — is an unstructured speed session where you vary your pace based on feel, terrain, or landmarks. Sprint to the next lamp post, jog to the tree, run hard up the hill, coast down the other side.
Fartlek is the most accessible form of speed work because it requires no track, no watch, and no rigid plan. It builds both aerobic and anaerobic fitness while keeping training fun and mentally fresh. It is particularly effective early in a training cycle when you want to introduce faster running without the structure of formal intervals.
Our fartlek training examples guide provides multiple session formats from beginner to advanced.
Strides
Strides are 20 to 30-second accelerations at roughly 90 percent effort, with full recovery between each. They are not sprints — strides should feel smooth, controlled, and relaxed at speed.
Strides improve your running economy, neuromuscular coordination, and leg turnover without adding meaningful fatigue to your training. Adding four to six strides to the end of two to three easy runs per week is one of the simplest and most effective speed improvements you can make. Read our guide to running strides for proper execution.
Hill Repeats
Running uphill at hard effort for 30 to 90 seconds, then jogging back down to recover. Hill repeats build leg strength, running power, and cardiovascular fitness simultaneously. They are a time-efficient alternative to track intervals and develop the strength needed for faster flat running.
VO2 Max Intervals
Efforts of three to five minutes at roughly your 3K to 5K race pace. These are the hardest sessions in a runner’s week and produce the biggest improvements in aerobic capacity. Four to six repetitions with three to four minutes recovery is a typical structure. These sessions should only be attempted once per week at most, and only after building a solid base. Our VO2 max workouts guide covers specific sessions.
How to Fit Speed Work Into Your Week
The most effective approach for recreational runners is one to two quality sessions per week, with the remaining runs at easy, conversational pace. This is the 80/20 principle — roughly 80 percent easy, 20 percent hard.
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| Day | Session | Purpose |
|---|---|---|
| Monday | Rest | Recovery |
| Tuesday | Intervals or tempo | Speed and threshold |
| Wednesday | Easy run + strides | Recovery and leg speed |
| Thursday | Easy run or rest | Recovery |
| Friday | Tempo or fartlek | Threshold and race fitness |
| Saturday | Easy run | Pre-long run recovery |
| Sunday | Long run | Endurance |
Allow at least 48 hours between hard sessions. Never stack two quality days back-to-back without an easy day or rest day between them. The hard sessions provide the stimulus; the easy days provide the recovery that allows your body to adapt.
Coach’s tip: If you only have time for one quality session per week, make it a tempo run. Tempo running provides the biggest return on investment for recreational runners because it improves your lactate threshold — the single biggest limiter for most race distances from 10K to marathon.
Progressing Your Speed Work
Speed work should progress gradually over a training cycle. Start with shorter, easier sessions and build towards longer, harder ones as race day approaches.
Early in training (base phase): strides after easy runs, fartlek sessions, and short tempo efforts of 10 to 15 minutes. The focus is on introducing faster running without heavy fatigue.
Mid-training (build phase): structured intervals of 400 metres to 1.6 kilometres, tempo runs of 20 to 30 minutes, and threshold intervals. The sessions get race-specific and the intensity increases.
Late training (peak phase): race-pace sessions, VO2 max intervals, and longer tempo runs of 30 to 40 minutes. You are sharpening fitness and building confidence for race day.
Final 10 to 14 days (taper): reduce volume significantly but maintain some intensity. Short, sharp sessions of strides and race-pace efforts keep your legs feeling quick without adding fatigue.
Common Speed Work Mistakes
Running too fast on easy days. If your easy runs are at moderate effort, you arrive at speed sessions already fatigued and cannot hit the targets that produce improvement. Use heart rate zones to keep easy days genuinely easy.
Doing too many hard sessions. More than two quality sessions per week increases injury risk for most recreational runners without proportional speed gains. Quality over quantity always wins.
Skipping the warm-up. Every speed session should begin with 10 to 15 minutes of easy running plus dynamic stretches. Jumping straight into hard efforts increases injury risk and reduces workout quality.
Ignoring recovery between repetitions. The recovery jog between intervals is not wasted time — it is what allows you to maintain quality on the next effort. Cutting recovery short degrades the session.
If you have been doing speed work consistently but are not seeing improvement, our guide on why you are not getting better at running identifies the most common bottlenecks.
Our running coaching builds your speed work around your current fitness, your goal race, and your available training time. Every interval, tempo, and threshold session has a clear purpose — no guesswork, no wasted effort.
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FAQ: Speed Work for Runners
What is the difference between a tempo run and intervals?
A tempo run is a sustained effort at lactate threshold pace for 20 to 40 minutes. Intervals are shorter, faster efforts with recovery jogs between each repetition. Tempo runs build your ability to sustain a hard pace. Intervals raise your top-end speed and VO2 max. Both are important and serve different purposes in a training plan.
How fast should I run my speed sessions?
Tempo runs should feel “comfortably hard” — roughly 25 to 30 seconds per kilometre slower than your 5K pace. Intervals at 5K to 10K pace. VO2 max efforts at 3K to 5K pace. Strides at about 90 percent effort. If you cannot maintain the target pace for the full session, you started too fast.
Can beginners do speed work?
Yes, but start gently. Strides and fartlek are the best entry points because they introduce faster running without rigid structure or high injury risk. After four to six weeks of consistent easy running, most beginners can safely add one structured speed session per week.
Will speed work help me in a marathon?
Absolutely. Tempo runs and threshold work are essential for marathon training because they improve your ability to sustain a hard pace for hours. Intervals and VO2 max work raise your aerobic ceiling, which makes marathon pace feel easier by comparison. Even marathon runners benefit from one speed session per week.
How do I know if I am doing too much speed work?
Signs include persistent fatigue on easy runs, elevated resting heart rate, declining performance in speed sessions, frequent minor injuries, and dreading training. If you experience these, reduce your speed work to one session per week and increase your easy running volume.
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